Ground Subsidence and Coastline Erosion Tuktoyaktuk Northwest Territories

Ground Subsidence and Coastline Erosion: Tuktoyaktuk, Northwest Territories, Canada Alec Aitken, Geography & Planning, 117 Science Place, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S 7 N 5 C 8 (alec. aitken@usask. ca) This learning activity is linked to 2 lectures that introduce students to permafrost, its distribution in the circumpolar region, the environmental factors that contribute to permafrost degradation, and the terrain response to permafrost degradation (e. g. , ground subsidence). In this exercise students explore topics related to permafrost, shoreline dynamics, hazards associated with ground subsidence, flooding and shoreline erosion, and community adaptations to these hazards. Students are assigned readings from peer-reviewed research articles. Small group discussions are employed to explore the salient points of each article. A question and answer session follows with the course instructor eliciting responses from students that address topics related to shoreline dynamics and the community’s response to rapid shoreline retreat and flooding. Shaw et al. (1998) present a model for coastline sensitivity to accelerated sea-level rise. The authors include a case study of rapid shoreline erosion associated with ice-rich permafrost at Tuktoyaktuk, NT. Tuk SI = √((a 1 x a 2 x a 3 x a 4 x a 5 x a 6 x a 7)/7) a 1 = relief (indicator of inundation risk); a 2 = rock type (associated with resistance to erosion); a 3 = coastal landform (indicator of sensitivity to coastal processes); a 4 = sea-level tendency (indicator of risk of inundation); a 5 = shoreline displacement rate (indicator of sensitivity to coastal processes); a 6 = mean tidal range (linked to inundation and erosion hazards); a 7 = mean annual maximum significant wave height (related to the capacity for erosion). Wolfe et al. (1998) present a case study of rapid shoreline erosion at Tuktoyaktuk. Ground subsidence associated with thawing permafrost has produced an over steepened foreshore which permits larger waves to attack the shoreline, especially during fall storms, contributing to rapid shoreline recession. The authors explore strategies for shoreline protection. Shore protection on the beach at Tuktoyaktuk is being undercut and eroded almost as quickly as it can he placed. Ford and Pearce (2010) explore community adaptive capacity to environmental change in the Inuvialuit Settlement Region of the western Canadian Arctic. In the case of Tuktoyaktuk community adaptation has focused on strategies for shoreline protection and community emergency evacuation plans to address flooding associated with storm surges at the coast. Aerial view of Tuktoyaktuk on the Beaufort Sea coast. Supporting Materials Shoreline retreat at Tuktoyaktuk, 1947 (green) to 1997 (black). Canadian Broadcasting Corporation News. Thawing permafrost sinks buildings, hikes costs in North. http: //www. cbc. ca/news/canada/story/2011/11/16/north-big-fix-permafrost. html J. D. Ford and T. Pearce. 2010. What we do know, do not know, and need to know about climate change vulnerability in the western Canadian Arctic: a systematic literature review. Environmental Research Letters. doi: 10. 1088/1748 -9326/5/1/0140089 National Ice and Snow Data Center. All About Frozen Ground http: //nsidc. org/cryosphere/frozenground/what_affects_fg. html J. Shaw, R. B. Taylor, S. Solomon, H. A. Christian and D. L. Forbes. 1998. Potential impacts of global sea-level rise on Canadian coasts. The Canadian Geographer, 42(4): 365 -379. S. L. Smith, M. M. Burgess and J. A. Heginbottom. 2001. Permafrost in Canada, a challenge to northern development. In G. R. Brookes (ed. ). A Synthesis of Geological Hazards in Canada, Geological Survey of Canada, Bulletin 548, pp. 241 -264. S. A. Wolfe, . S. R. Dallimore and S. M. Solomon. 1998. Coastal permafrost investigations along a rapidly eroding shoreline, Tuktoyaktuk, N. W. T. 7 th International Permafrost Conference (Proceedings), Yellowknife, Canada. Collection Nordicana, No. 55, pp. 1125 -1131.